Gear holding and centralizing device



Oct. 18, 1932. D. C.-PAGE GEAR HOLDING AND CENTRALIZING DEVICE Filed Feb. 27, 1932 Dwight 81 @z.

Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE DWIGHT C. PAGE, 0] 'WOBGESTEB, HASSAOHUSETTS, ASSIG NOB 1'0 THE Elm mom COMPANY, 03' WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS GEAR HOLDING AN D CEHTRALIZING DEVICE Application filed February 8?, 1932. Serial No. 595,441.

The present invention relates to animproved gear holding and centralizing device which is adapted to support a toothed gear with reference to a pitch line or circle so that a grinding or cutting operation performed on an internal opening in the gear, Will be obsolutely concentric or coaxial with the pitch circle of the teeth and the device is particularly adapted for the support of gears having teeth oi the helical type.

The Heald Patent No. 1,058,237, granted April 8, 1913 discloses the use oi? cylindrical pins in clamping spur gears concentrically Within a chuck or Work-holder, the cylinc dricsl pins engaging the surfaces of adjecent rear teeth along the pitch line, and the jaws the chuck engaging said cylindrical pins, thereby centering the gear and clamping it securely in the chuck. Such a construction, how-ever, is not applicable to helical gear teeth since strai ht c lindrical ins cennot engage along the pitch line of this type oiteeth over the entire length by reason the curvature oi the teeth. The invention disclosed in the copending application ofGheralcl D. Scott, Serial No. 514,585 was arranged to overcome the dis advantages oi the construction in the above noted Heald pamnt by providing it gear hold- 0 ing device by which a plurality of pairs of spherical or elliptical members Were positioned in spaced relation around the periphcry of a gesneach pair of members being positioned between adjacent gear teeth and being of a size to engage said teeth substantially at the pitch line. The gear is positioned in the chuck by this device through engagement of the jaws of the chuck With the spherical or elliptical members, and the necessarily high pressures exerted by the chuck jaws exerted on the spherical members in clamping the gears securely in the chuck by means of this device result, especially when the gears are of soft material, in permanent small depressions in the faces of the gear teeth. Although these depressions do not effect the operativeness and strength of the gear, they are apparent upon close inspection and often efl'ect the solubility of the gear. Accordingly, one of the principal objects of large in diameter to engage ndjccent teeth oi a gear substantially along the pitch line thereof, and which are suhiciently long to extend over sulcsts tielly the entire width of line contact with the laces of gccr test over the entire length thereof, to ddst'rib the clamping pressures from. the

over a. large area in certain aspects dcvice constitutes on inr'rovement over the cen tralized device descri' ed. in the shove noted copending spplicotion of Scott 514,565.

The advantages end objects of the 'tion Will appear from the toilet-ring dcecription with reference to the nccoinpnnying drawing in which Fig, l. is it view partly in section showing a gear l old in a suitehle clinch by inesns oi the centralizing device,

Fig. 2 is a side elevation of the centralic inc" device.

4. lg. 3 is a ilinginentary plan view showing it modification of the device in position on helical gear,

Fig. l is a fragmentar view ill'ustretin the cooperation of the device with the teeth e gear and the jaws of a, chuoli.

Like reference characters refer to like parts in the different figures.

Referring to Fig. 2, the invention coni=- prises a base member 1 in the form of a ring which provides a plurality o'l recesses 2 in which are mounted flexible arms or supports 3, the latter extending "from the bsse l at points suitably spaced around its "periphery. The arms or supports 3 extend through openings 4 in the lease and the ends thereof are bent over for reception in slots 5 in the base The flexible members thus have member 1 opposite each recess, the ends of said arms being securely held in said slots, as by solder 6. Each of the arms 3 carries a resilient work-engaging member 7 substantiall circular in cross-section, which is held on the arm 3 by spaced collars 8 and 10 attached to said arm.

The diameter of the base member 1 is determined by the pitch diameter of the gear to be held and the size of the work-engaging portions 7 is determined b the circular pitch of the gear teeth. In use t e device is slipped over a gear 11, Figs. 1 and 4, with the base 1 substantially engaging and parallel to the the side of'the gear and the arms 3 extending over the faces of the ear teeth 12. With the ring 1 so positioned, t e work-engaging members 7 on the arms 3 lie between adjacent gear teeth 12 and engage opposed faces of the teeth substantially at the pitch line, the flexibilitg of the arms 3, as well as the resiliency of t e members 7 permitting said members to position themselves readily between adjacent gear teeth with the members 7 engagin said teeth over substantially the entire width of the gear face so that the gripping action of the work-engaging members 7 is distributed over a large area.

The number and spacing of the arms 3 coincides with the number and spacin of the radially movable jaws 13 of a chuc 14 of usual construction such as shown in Fig. 1, so that when a gear 11 held by the arms 3 is placed in the chuck 14 and thejaws 13 contracted, the work-enga ing portions 7 will simultaneously engage t e gear teeth 12 and hold the gear firmly in position, and since the work-enga ing members en a the gear teeth 12 su tantiall around t e pitch circle, as indicated in ig. 4, the surfaces of these portions 7 engage all the chuck jaws 13 at the same distance from the center of the pitch circle. Consequently any grinding or cutting operation performed on the interior of the central opening 15 of the ar 11 as the chuck rotates will be absolute y concentric or coaxial with the pitch circle of the teeth 12.

In the modification disclosed in Fig. 3, the

v flexible arms 3 are arranged in pairs, with the arms of each pair secured tothe base member 1' in the manner above pointed out P with reference to the construction of Fig. 2, and each arm 3' supports a. work-engaging member 7 between spaced collars 8' and 10'. The arms 3' of each pair are spaced apart in accordance with the spacing of ad'acent teeth on the gear to be clamped in or er that the work-engaging member 7' on the arms of each pair may lie in the grooves between successive gear teeth as shown in Fig-t3, both said work-engaging members of each pair "to'be engaged by a single jaw of the chuck.

' The resilient work-engaging member 7 or the member 7' of Fig. -3 which, as above rality of flat surfaces, all equally spaced from r the axis of the work-engaglng member, there by providing a substantiall continuous surface for engagement with t e gear teeth. It will be noted that, by reason of the coil construction, the members 7 or 7 are resilient, the axis ofsaid members being deformable by a bending'action whereby the may be bent to conform to the curvature of t e gear teeth, but at the same time, said members are sufiicientl rigid to prevent cross-sectional, or radia distortion, as a result of the clamping action of the chuck jaws, thus maintaining the original circular cross-section.

In t e use of the device 'since the workengaging members are cylindrical, the portion of the surface of the work-engaging members remote from the center of the gear defines a cylindrical surface parallel to the cylindrical surface defined by the'pitch line gear so that wh n the chuck jaws 13 are to the proper 'ameter with the workter of the workpiece along the entire length Y thereof, as best shown in Fig. 4. Thus the clam ing action between the jaws of the chuc and the wor iece is over substantially the entire width 0 the above stated, substantial y straight line contact between the work-engaging members and the iar teeth over substantially the entire lengt of the work-engaging members.

When utilizing gear centralizing devices embodying the present invention, it is necessary to rovide a varie of sizes corresponding to e various pitc diameters of workieces to be 0 rated upon the work-contactmg portions being of such size as to contact with the gear teeth substantially at the pitch line. When it is desired to centralize a gear or workpiece of a predetermined size, a detle chuck jaws defining.

ar, providing, as

vice is selected of the proper diameter with work-contacting portions of thesize required for engagement roperly with the teeth after which the flexib e arms 3 are adjusted to aproximate the angularity of the gear teet 11 making such adjustments the 2 permit the flexible arms to be bent with a comparatively large radius at the points where they are held by the rings avoiding the danger of breaking the arms by repeated bending. The arms 3 having been bent to a proximate the angle of the gear teeth, and e gear with the device thereon having been placed in the chuck, the jaws thereof are actuated and the work-en aging members ac= commodate themselves, y reason of their resiliency to the spaces between adj acent gear teeth.

I claim,

1. A device for centeringa 11811031 gear, comprising a base member, a lurality of flexible arms extending from sald base, and

resilient members on each of said arms for engagement with the teeth of said gear on the pitch line.

2. A device for centering a gear in a clamping device, comprising a base member, a plurality of resilientmembers extending from said base for engagement between teeth on said gear and the clamping device, said members being so spaced as to enga e the gear teetii at diflerent points around the pitch cn'c e.

3. A device of the class described comprising a series of flexible cylindrical members for engagement between adjacent teeth on a gear and of such a size as to engage the gear teeth substantiall on the pitch line, and means to hold saii? members in position.

39 4. A device for centering a gear in a clamping device, comprising a base member, flexible arms carried by said base and resilient members substantially circular in cross-section on each of said arms'for engagement between 5 adjacent gear teeth, the diameter of said resilient members being'such as to engage the gear teeth substantially at the pitch line.

5. A device for centerin a gear in a clamping device, comprising a Ease, a plurality of 40 flexible arms and a plurality .of cylindrical members on said arms, said members being axially flexible for enga ement with the teeth of a gear substantla y along the pitch line thereof over substantially the entire length of the gear teeth.

6. A device for centering a helical gear in a clamping device, comprising an annular base, and cylindrical members carried by said base, said cylindrical members being substantially rigid in cross-section and deformable axially by a bending action, whereby said members may be shaped to engage the teeth of the gear substantially along the pitch line throughout the width of said gear.

7. A device for centering a ear in a clamping device, comprising a ase, and coil springs carried by said base for engagement with the teeth of said ear substantially along the pitch line thereo. a vDWIGHT C. PAGE. 

